The present invention relates generally to a method and a device for winding tubes around a core in the manufacture of heat-exchangers.
The invention is more particularly concerned with a method of the above type, wherein at least one winder assembly is subjected to a combined translational and rotational movement resulting in the winding of at least one tube around a core.
There are already known heat-exchangers obtained by the afore-mentioned method and comprising a great number of tubes wound to a helical form in a certain number of layers around a core. More precisely, such exchangers were manufactured by positioning a core vertically at the centre of a cabin equipped with a certain number of members, the combined ascending, descending and rotational movements of which ensured the required winding.
The said members were essentially as follows:
A VERTICALLY MOVABLE PLATFORM,
A HORIZONTAL CROWN OR TOP MEMBER CONCENTRIC WITH THE CORE AND SUPPORTED BY POSTS AND BRACKETS ABOVE THE SAID PLATFORM, AND
FOUR WINDERS SPACED 90 DEGREES FROM ONE ANOTHER, SUSPENDED FROM THE SAID CROWN AND ADAPTED TO ROTATE ABOUT SAID CORE TO ALLOW THE TUBES TO BE WOUND THEREON TO A HELICAL FORM.
Such a construction remained quite complicated as regards both its structure and its operation. Indeed the winders moved vertically by rotating between a lower end position and an upper end position, i.e., substantially between the platform and the crown from which the winders were suspended, and when the winders reached the upper end position in proximity to the crown the platform was actuated vertically and automatically so as to raise the whole device along the core and perform the winding around an upper portion of the core.
Such an installation suffered also from a certain number of other disadvantages, for example where large-surface exchangers were required.
The winders suspended from the crown were highly unstable owing to the varying forces to which they were subjected. This resulted in inaccurate winding, repeated adjustments and therefore slow manufacture. Breakage could even occur at the winders and access to the latter was difficult owing to the complexity of the installation described above.
The said disadvantages resulted in frequent damage to the machine and possibly to the tubes themselves during the winding.
Moreover, in regard to a good deal of the production, the excessively large winders allowed for the winding of only two tubes during each upward travel. In addition each suspended winder could wind only one tube during each upward travel of the platform.
It may also be mentioned that the platform arranged concentrically with the core was difficult to dismount as the diameter of the coil increased. Lengthy and frequent winding stoppage was therefore necessary.
The object of the present invention is to remedy all the afore-mentioned drawbacks by providing a winding method and a winding device which are simple and particularly efficient. The device according to the invention allows several layers of tubing to be wound on a core within a very short time and with high accuracy ensuring excellent winding reliability.